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Bulletin  16] 


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The  Agricultural  Experiment  Station 


OF  THE 


Colorado  Agricultural  College 


CEMENT  AND  CONCRETE  FENCE  POSTS 


BY 


H.  M.  BAINER 
H.  B.  BONEBRIGHT 


PUBLISHED   BY  THE   EXPERIMENT  STATION 

FORT  COLLINS.  COLORADO 

1910 


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The  Agricultural  Experiment  Station 


FORT  COLLINS,  COLORADO 


THE  STATE  BOARD  OF  AGRICULTURE 

Term 
Expires 
Hon.  B.  F.  ROCKAFKIyl^OW, Canon  aty,         1911 

Hon.  K.  H.  GRUBB, Carbondale,  1911 

Hon.  R.  W.  CORWIN, Pueblo,  1913 

Hon.  a.  a.  EDWARDS,  President,        ...        -      Fort  Collins,  1913 

Hon.  F.  B.  BROOKS,  Colorado  Springs,  1915 

Hon.  J.  Iv.  BRUSH, Greeley,  1915 

Hon.  J.  C.  BEIvIv, Montrose,  1917 

Hon.  E.  M.  AMMONS, Ivittleton,  1917 

Governor  JOHN  F.  SHAFROTH     )  ^^  nm^-:^ 
Prrsidsnt  CHAS.  a.  IvORY      ^  \  ^^-^i^icio. 

I^.  M.  TAYIvOR,  Secretary  G.  A.  WEBB,  Treasurer 


J.  ly.  BRUSH, 


EXECUTIVE  COMMITTEE  IN  CHARGE. 

A.  A.  EDWARDS  Chairman. 


E.  M.  AMMONS 


STATION  STAFF 

I^.  G.  CARPENTER,  M.  S.,  Director,       -        -        -  Irrigation  Engineer 

C.  P.  GIIylvETTE,  M.  S., Entomologist 

W.  P.  HEADDEN,  A.  M.,  Ph.  D.,  Chemist 

G.  H.  GLOVER,  M.  S.,  D.  V.  M., Veterinarian 

ALVIN  KEYSER,  A.  M. Agronomist 

J.  O.  WIIvLIAMS,  B.  S.  A.,  U.  S.  Expert  in  Charge  -  Horse  Breeding 
W.  G.  SACKETT,  B.  S., Bacteriologist 

E.  R.  BENNETT,  B.  S.,  Horticulturist 

P.  K.  BIvINN,  B.  S.,  Rocky  Ford  -  -  Field  Agent,  Arkansas  Valley 
R.  E.  TRIMBLE,  B.  S.,  ...  Assistant  Irrigation  Engineer 

F.  C.  AIvFORD,  M.  S., Assistant  Chemist 

EARIv  DOUGLASS,  M.  S ,  -        -        -        -  Assistant  Chemist 

S.  ARTHUR  JOHNSON,  M.  S.,  -        -       -  •         Assistant  Entomologist 

B  O.  LONGYEAR,  B.  S., ASSISTANT  Horticulturist 

MIRIAM  A.  PALMER, Delineator 

L.  C.  BRAGG, Ass'T  in  Entomology 

C.  L.  FITCH, Potato  Investigations 

H.  M.  BAINER,  M.  S.,  ...        .        Dairying  and  Farm  Machinery 

G.  E.  MORTON,  M.  L.,  B.  S.  A.,  -  -  -  -  Feeding  Investigations 
G.  C.  KREUTZER,  B.  S.,  .  -  -  Ass'T  Irrigation  Investigations 
GEORGE  P.  WELDON,  B.  S.,  Grand  Junction.  -  Field  Entomologist 
R.  S.  HERRICK,  B.  S.,  Delta,       ....  Field  Horticulturist 

W.  E.  VAPLON, Poultry 

J.  E.  PAYNE,         ....  .        .       Field  Agent,  Plains 

J.  W.  ADAMS,  Cheyenne  Wells,        ....       Sup't  Sub-Station 

JAMES  HUTTON,        .        -        . Groom 


MATERIALS  USED  IN  CONSTRUCTING,  j^m^'^ 
AND  CONCRETE  FENCEF'P^ST^AunjfaMt^ 

By  H.  M.  BAINER  and  H.  B.  BONEBRIGHT 


PART    I. 
GENERAL  STATEMENTS 

Cement. — In  cement  fence  post  construction,  it  is  desirable 
that  the  post  be  made  as  li^ht  and  as  strong  as  possible,  and  thus 
it  is  practical  to  use  nothing  but  the  best  grade  of  Portland 
cement. 

Sand. — Clean,  sharp  sand  with  grains  varying  in  size  from 
small  to  large  makes  the  best  mixture.  Sharp  sand-  is  composed 
of  sharp,  angular  grains  of  all  sizes  and  makes  a  better  mixture  than 
that  which  is  smooth  and  round,  or  "river-worn." 

A  sand  composed  of  fine  and  coarse  grains  mixed,  is  to  be 
preferred,  because  less  cement  will  be  required  to  fill  the  voids  than 
either  used  by  itself. 

Leaves,  sticks,  stones  or  gravel  should  be  removed  by  screening. 

Gravel. —  The  same  general  rules  used  in  the  selection  of  a 
good  grade  of  sand  will  apply  to  gravel.  It  should  be  composed 
of  clean,  sharp  pebbles  of  all  sizes.  For  post  construction,  the 
pebbles  must  not  be  too  large,  as  they  will  interfere  with  the  proper 
placement  of  reinforcement. 

Broken  Stone. — Broken  stone  used  for  post  construction 
must  contain  no  large  pieces  as  they  will  interfere  with  the  place- 
ment of  the  reinforcement.  It  is  necessary  to  use  sortie  sand  with 
the  stone  to  fill  voids  and  thus  save  cement.  It  is  not  desirable  to 
use  soft  sandstone,  soft  limestone,  slates,  or  shales.  Granites,  hard 
limestones,  and  coarse  gravel,  which  has  been  crushed,  is  considered 
best. 

Water. — The  water  used  in  making  a  cement  or  concrete 
mixture  should  be  clean  and  free  from  alkali  or  acids. 

Proportions. — On  account  of  the  difference  in  the  total 
open  space  or  voids  in  sands  or  gravel  composed  of  different  sized 
particles  and  also  that  more  cement  is  required  in  some  conditions 
than  in  others,  it  is  often  necessary  to  make  a  rough  determination 
of  the  percentage  of  voids  to  the  total  aggregate.  Where  maximum 
strength  is  required  about  lo  per  cent,  more  cement  should  be  used 
than  the  total  voids. 

The  determination  may  be  made  as  follows :  Secure  a  water- 
tight box  or  pail  of  known  capacity,  fill  it  with  the  aggregate  to  be 
used  so  that  when  it  has  been  well  shaken  it  will  smooth  off  even 

*  This  bulletin  is  an  abbreviated  edition  of  Bulletin  No.  148  of  June, 
1909.  A  large  part  of  the  details  of  the  tests  have  been  omitted,  but  all 
the  important  results  are  summed  up  in  the  tables  here  presented. 


496123 


4  The  C01.ORAD0  Experiment  Station 

at  the  top.  Pour  water  of  known  amount  into  this  until  full.  The 
volume  of  water  used  in  proportion  to  the  total  volume  of  the 
receptacle  determines  the  total  voids. 

The  proportions  used  in  the  constructions  of  the  fence  posts 
in  this  bulletin  varied  from  i  part  cement  and  3  parts  of  sand  to 
I  part  of  cement  and  5  parts  sand.  In  others,  gravel  was  used  in 
the  proportion  of  i  part  cement,  3  parts  sand,  and  3  parts  gravel. 
It  is  a  difficult  matter  to  use  broken  stone  or  gravel  in  large  quan- 
tity and  place  the  reinforcement  properly. 

Measure  all  materials  in  correct  proportions.  This  may  be 
done  with  a  shovel,  a  pail,  wheelbarrow,  or  barrel.  It  will  usually 
be  advantageous  to  measure  the  water,  especially  where  small  quan- 
tities are  mixed  or  where  the  same  amount  of  mixture  is  made  sev- 
eral times. 

Mixing. — Where  the  mixing  is  done  by  hand,  a  flat,  water- 
tight platform,  or  shallow  box  is  convenient.  Measure  the  sand 
and  place  it  in  a  uniform  layer  and  over  this  spread  the  proper 
amount  of  cement.  Mix  this  thoroughly  before  adding  water  until 
it  shows  a  uniform  color.  The  rule  is  to  shovel  it  over  at  least 
three  times.  Now  spread  out  the  mixture,  making  a  sort  of  basin 
in  the  middle  into  which  the  greater  part  of  the  water  may  be 
poured.  Work  in  the  dry  edges  until  the  water  disappears,  then  add 
enough  more  water  in  small  amounts  to  make  the  mixture  of  the 
desired  consistency.  Do  not  mix  more  material  than  can  be  used 
in  twenty  minutes. 

Poured  Posts. — There  are  two  general  classes  of  mix- 
tures which  may  be  used  in  the  construction  of  posts ;  the  poured 
and  the  tamped.  In  the  poured  mixture,  enough  water  is  used  in 
mixing  to  make  it  thin  enough  to  pour  from  a  pail  or  scoop  almost 
like  water.  The  mixture  is  poured  into  a  mold  and  allowed  to  re- 
main in  it  until  it  has  set,  which  is  from  one  to  five  days,  depending 
upon  the  time  of  year  and  the  weather.  In  drying  summer  weather, 
from  one  to  two  days  is  usually  sufficient.  In  cool  or  damp  weather, 
they  must  be  left  in  the  molds  much  longer. 

In  order  to  make  several  posts  of  the  poured  type  at  once,  it  is 
necessary  to  have  several  molds  ready  for  use.  With  6  molds  only 
6  posts  could  be  made  at  once,  and  it  would  be  necessary  to  wait 
until  the  cement  was  set  before  6  more  could  be  made. 

It  was  found  that  to  make  a  good  poured  post,  the  mixture 
should  be  stirred  or  shaken  immediately  after  placing  in  the  mold. 
This  should  be  done  carefully  to  prevent  displacement  of  reinforce- 
ment wires.  This  helps  to  remove  the  air  from  the  mixture  and 
makes  a  post  of  smooth  finish. 

The  experiment  showed  that  a  poured  post  of  a  certain  mix- 
ture was  stronger  than  a  tamped  post  of  the  same  mixture.     It  is 


Cement  and  Concrete  Fence  Posts.  5 

enough  stronger  to  justify  anyone  in  constructing  it  in  preference 
to  the  tamped  one  at  the  necessary  additional  expense  for  molds. 
The  poured  post  is  smoother,  more  nearly  impervious  to  water,  not 
so  hard  to  cure,  stronger,  somewhat  more  expensive,  and  can  be 
better  recommended  than  the  tamped  one. 

Tamped  Posts. — The  tamped  post  is  one  in  which  the 
mixture  contains  very  much  less  water  than  the  poured  one.  It 
contains  just  enough  water  to  make  it  hold  together  well  when 
tamped.  In  the  manufacturing  of  this  type  of  post,  only  one  mold 
is  necessary.  The  mixture  is  tamped  into  it,  and  the  sides  of  the 
mold  can  be  removed  immediately,  the  post  remaining  on  the  bot- 
tom piece  until  the  cement  has  set.  Thus  the  same  mold  can  be  con- 
tinuously used  for  making  as  many  posts  as  are  desired.  The  ne- 
cessity for  but  one  mold  makes  this  type  of  post  less  expensive  than 
the  poured  one.  The  results  of  the  test  made,  show  that  the  tamped 
post  is  inferior  to  the  poured  one  and  cannot  be  placed  in  an  equal 
class  with  it. 

On  account  of  less  water  being  used  in  the  mixture  for  a 
tamped  post  than  in  the  mixture  for  a  poured  one,  the  tamped  post 
reqtiires  more  water  and  attention  in  curing.  It  is  of  more  open 
texture,  less  impervious  to  water,  not  as  strong,  and  not  as  desir- 
able as  the  post  of  the  poured  type. 

Molds  For  Tamped  Posts. — In  this  class  of  molds  we  find 
mostly  the  heavy  cast-iron  forms  which  are  built  of  strong 
and  heavy  material.  The  most  of  these  molds  are  designed  to  be 
laid  upon  pallettes  or  upon  a  smooth  floor.  The  mixture  is  first 
tamped  into  the  mold  to  a  depth  of  about  one  inch.  The  reinforce- 
ment is  then  placed  and  the  mold  is  next  filled,  and  the  mixture 
tamped,  so  that  only  about  one  inch,  of  material  remains  to  be 
filled  in.  The  second  set  of  reinforcement  wires  is  put  in  place 
next  and  the  mold  is  tamped  full  to  overflowing.  The  last  step  con- 
sists in  smoothing  off  the  top  of  the  post  with  a  trowel  and  re- 
moving the  mold.  This  is  done  by  unfastening  some  form  of  hook 
or  clasp,  slipping  the  sides  of  the  mold  a  little  distance  away  from 
the  post,  and  then  removing  the  molds  to  the  position  chosen  for 
the  next  post. 

The  principal  advantage  of  these  molds  lies  in  the  fact  that 
they  being  made  of  heavy  iron  need  no  center  stays.  This  gives 
greater  speed  in  operation,  due  to  the  fact  that  there  are  no  cross 
pieces  to  interfere  with  the  placing  of  the  reinforcement,  the  tamp- 
ing of  the  mixture,  and  the  smoothing  off  of  the  top  of  the  post  at 
the  finish. 

Molds  for  Poured  Posts. — The  more  common  forms  are 
made  of  sheet  iron,  either  galvanized  or  plain.  For  posts  having 
a  continual  taper  from  top  to  bottom,  sheet  iron  molds  prove  very 


6        The  Colorado  Experiment  Station 

satisfactory,  providing  sufficiently  heavy  material  is  used  in  their 
construction. 

The  advantages  of  the  sheet  iron  mold  are  many.  They  are 
light  to  handle  and  easy  to  keep  clean.  If  properly  made  they  are 
nearly  water  tight.  This  insures  the  user  against  the  possible  loss 
of  cement  by  leakage.  Another  marked  advantage  of  the  sheet-iron 
mold  is  that  the  surface  being  smooth,   imparts  a  very  smooth, 

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Figure  I. 

A  Home  Made  Mold  Giving  the  Proper  Shape  to  the  Post. — 1.  Base 
fastener.  2.  Base  end  piece.  3.  Ground  line  fastener.  4.  4,  etc.  Tie 
hole  pins.  5.  Top  piece  pin.  6.  Top  end  piece.  7.  Top  fastener  A. 
Side  of  mold.     B.     Pallette. 


I 


glossy  finish  to  the  surface  of  the  post.  This  not  only  adds  beauty 
to  the  post,  but  aids  in  keeping  out  water,  which  might  otherwise 
enter  the  cured  post. 

As  the  sheet-iron  molds  are  made  in  one  piece,  no  pallette  is 
necessary.  In  hot  weather  the  post  may  be  removed  after  48  hours, 
but  in  cold  weather  a  much  longer  time  is  required. 


Cement  and  Concrete  Fence  Posts.  7 

In  making  poured  posts  in  these  molds  exactly  the  same  pro- 
cess is  followed  as  with  tamped  posts  in  molds  of  the  first  class  just 
described ;  with  the  exception  that  the  mixture  is  not  tamped  and 
greater  care  must  be  exercised  in  preventing  the  reinforcement  from 
being  misplaced. 

Some  forms  of  wood  molds  are  made  and  used  for  the  purpose 
of  making  poured  posts  only.  Any  desired  form  may  be  given  to 
the  post  by  properly  shaping  the  mold.  This  point,  in  favor  of  the 
wood  mold,  is  an  extremely  important  one,  as  it  permits  the  post  to 
be  made  of  uniform  size  from  the  bottom  to  the  ground  line,  but 
with  a  rapid  taper  from  this  point  to  the  top.  Then  too,  the  sides 
of  the  mold  may  be  removed  after  24  hours  and  used  again  in  con- 
nection with  other  pallettes;  while  the  post  which  has  not  yet  be- 
come sufficiently  strong  to  be  removed  from  the  pallette  lies  un- 
molested in  its  original  place  until  it  is  ready  to  move. 

Molds  which  may  be  used  for  making  either  the  tamped  or  the 
poured  posts  are  much  the  same  as  the  wooden  molds  for  poured 
posts,  except  that  they  are  stronger.  The  heavy,  cast-iron  molds 
could  be  used  in  making  the  poured  posts  as  well  as  the  tamped 
ones,  but  their  original  cost  make  them  impracticable.  The  wooden 
molds  serve  the  purpose  equally  well  and  are  much  cheaper. 

Selecting  the  Mold. — The  most  important  point  to  be  con- 
sidered in  selecting  the  mold  is  the  shape  and  size  of  it.  Next 
to  the  shape  and  size  we  should  look  for  ease  of  operation.  The 
simple  mold  almost  always  proves  to  be  the  best,  providing  it  has 
sufficient  strength. 

Care  of  Molds.^Beiore  the-  molds  are  used  they  should 
be  well  coated  with  some  kind  of  heavy  oil.  Crude  petroleum  is 
perhaps  the  best  and  cheapest  material  for  this  purpose.  In  case 
the  petroleum  cannot  be  obtained,  a  good  oily  mixture  may  be  made 
by  stirring  about  two  pounds  of  axle  grease  into  a  gallon  of  gaso- 
line. This  mixture  is  applied  to  the  molds  with  a  brush.  The 
gasoline  evaporates,  leaving  a  thin  coat  of  axle  grease  spread  over 
the  entire  surface  of  the  mold.  This  oily  mixture  should  be  ap- 
plied to  the  outside  as  well  as  the  inside  of  the  mold,  which  makes 
it  impossible  for  any  of  the  material  to  cling  to  it.  With  the  iron 
molds,  the  oil  prevents  rusting.  In  case  the  molds  are  made  of 
wood,  the  oil  helps  to  keep  out  the  moisture,  thus  preventing  shrink- 
ing and  swelling,  and  also  making  them  easier  to  keep  clean. 

As  soon  as  the  mold  is  removed  from  the  post  all  material 
sticking  to  it  should  be  scraped  off  and  the  inside  surface  covered 
with  a  thin  coating  of  oil.  Great  care  should  be  taken  not  to  allow 
the  molds  to  become  bruised  or  dented.  If  the  molds  are  not  to  be 
used  for  a  time,  they  should  be  thoroughly  scraped  and  oiled,  inside 
and  out,  and  carefully  laid  away. 


8  The  Colorado  Experiment  Station 

Reinforcement. — Cement  and  concrete  work  has  the  prop- 
erty of  resisting  great,  crushing  stresses,  but  when  subjected 
to  tensile  stress  the  best  of  it  breaks  very  easily.  For  this  reason 
it  becomes  necessary  to  put  some  material  possessing  great  tensile 
strength  into  the  post,  in  order  that  the  full  crushing  strength  of 
the  cement  or  concrete  may  be  utilized.  Iron  is  the  most  satis- 
factory material  from  which  to  make  reinforcement.  The  rein- 
forcement should  be  placed  in  the  post  as  near  the  corner  as  pos- 
sible. This  places  it  as  far  as  possible  from  the  neutral  axis  thus 
giving  it  the  greatest  advantage  in  strengthening  the  post.  In 
order  that  the  reinforcements  may  be  properly  held  and  protected 
by  the  cement,  it  is  a  good  plan  to  place  it  from  ^  to  ^  inch  in 
from  each  side. 

The  material  used  for  reinforcement  should  be  strong,  light 
and  rough  enough  to  permit  the  mixture  to  get  a  firm  grip  upon  it. 
It  should  be  very  rigid,  with  little  or  no  tendency  to  spring  or 
stretch.  The  experiments  showed  that  ordinary  iron  or  steel  wire 
was  cheapest,  strongest  and  easiest  to  procure.  In  order  to  provide 
a  means  by  which  the  cement  may  cling  firmly  to  the  wire,  it  is 
best  to  twist  two  small  wires  together  instead  of  using  one  large 
one. 

Curing  the  Posts. — In  order  for  the  cement  to  become 
thoroughly  cured  or  "set"  water  must  be  supplied  to  aid  in  the 
action.  For  the  first  thirty  days  the  posts  should  be  kept  wet  if 
the  best  results  are  to  be  expected. 

The  most  favorable  conditions  for  conserving  the  moisture 
consists  in  curing  the  posts  in  a  shed  where  the  wind  does  not 
strike  them.  Under  these  conditions  neither  the  sun's  rays  nor 
the  wind  have  a  chance  to  dry  out  the  posts  too  rapidly.  The  posts 
should  be  thoroughly  sprinkled  every  day  for  at  least  thirty  days. 

Wire  Fasteners. — An  inventor  has  devised  a  cast-iron  socket 
which  is  placed  in  the  post.  Later  the  wire  is  fastened  to 
the  post  by  driving  a  staple  into  the  socket  or  staple  holder.  The 
staples  pull  out  easily  and  the  sockets  add  greatly  to  the  cost  of 
the  post. 

Another  system  consists  of  two  staples  which  have  the  prongs 
bent  to  the  side.  The  staples  are  placed  about  one-quarter  inch 
apart,  with  the  prongs  projecting  to  the  side.  The  line  wire  is 
placed  between  the  two  staples  and  a  nail  or  a  piece  of  wire  is 
driven  down  through  the  staples,  outside  of  the  line  wire.  As  the 
tips  of  the  staple  touch  the  reinforcement  wires,  direct  electric  con- 
nections are  established  between  the  line  wire  and  the  ground  at 
the  bottom  of  the  post.  This,  it  is  claimed  by  the  patentee,  insures 
the  user  against  loss  of  stock  by  lightning.  The  system  is  called 
the  "Double  Staple."     (See  Fig.  2.) 


Cement  and  Concrete  Fence  Posts.  9 

A  "single  staple"  may  also  be  used,  but  the  wire  is  fastened 
to  the  staple  by  a  small  "cold  shut  link,"  or  wire  ring.  The  latter 
system  is  not  a  very  strong  method  of  fastening,  owing  to  the  ease 
with  which  the  cold  shut  links  open.     (See  Fig.  2.) 

Perhaps  the  most  common  method  of  fastening  wires  to  cement 
or  concrete  posts  consists  of  tying  in  the  line  wire  to  the  post  by 
means  of  a  piece  of  smaller  wire  called  a  "tie  wire"  (usually  No. 
14  or  No.  15  wire).  The  single  tie  consists  of  wrapping  one  end 
of  the  tie  wire  three 'or  four  times  around  the  line  wire,  then 
passing  the  long  end  through  a  hole  in  the  post  and  bringing  it 
around  to  the  face  of  the  post  where  it  is  also  wrapped  around  the 
line  wire.     (See  Fig.  2.) 


Ifej^     IWWl      lUjcW^ 


CROSSS€Cr/ONSB£L  OW. 


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- 

S/A/Cl£  r/r.      DOUBL  £  r/€. 

A 


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rAC£  V/£W. 


CROS'S  S£CT/ONS. 


i^ 


FAC£  Vt£W. 


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TMROi/CUcO. 


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B 


Figure  II. 

Different  Types  of  Wire  Fasteners. — A.    Home  made  fasteners.     B. 
Commercial  fasteners. 


The  tie  around  post  is  much  the  same  as  the  single  tie,  except 
that  the  tie  wire  passes  around  the  post  instead  of  through  the 
hole.  (See  Fig.  2.)  Neither  the  single  tie  or  the  tie  around  post 
are  very  strong  unless  the  tips  of  the  tie  wire  are  hooked  over  the 


lo  The  C01.0RAD0  Experiment  Station 

body  of  the  tie  wire  after  the  wraps  have  been  made.  This  is  known 
as  the  "special  tie." 

The  strongest  and  perhaps  the  most  satisfactory  system  of 
tying  in  the  wire  is  the  ''double  tie."  The  tie  wire  is  bent  into  the 
form  of  a  long  staple,  straddled  over  the  line  wire  and  both  ends 
passed  through  a  hole  in  the  post.  One  end  is  brought  to  either 
side  and  wrapped  about  the  line  wire  at  the  face  of  the  post.  This 
system  insures  a  solid  fastening  and  is  equal  in  strength  to  any 
ordinary  wood  post  fastening. 

The  holes  in  the  posts  are  formed  by  No.  6  wires  being  placed 
in  the  post  while  it  is  soft.  These  wires  are  called  "Tie  Hole  Pins." 
(See  Fig.  i.)  They  are  removed  from  the  poured  post  after  the 
cement  has  set  for  24  hours.  The  pins  are  removed  from  the 
tamped  posts  immediately  before  the  molds  are  removed. 

The  following  table  shows  the  comparative  holding  strength 
of  various  wire  fasteners,  as  determined  by  the  tests : 


WIRE  FASTENERS 
(See  description  of  same) 

KIND 

OF 
POST 

No.  I.bs. 

Required 

to  Pull 

Fastener 

REMARKS 

Ordinary  1%  inch  staple 

New 
Cedar 

425 

Average  of  3  pulls. 

Staple  was  well  driven  into  post. 

Single  special  tie 

Cement 

520 

Average  of  2  pulls.     Fence  wire  broke. 

Double  tie 

Cement 

510 

Average  of  2  pulls.     Fence  wire  broke. 

Double  staple 

Cement 

245 

Average  of  3  pulls.    Staples  pulled. 

No.  14  wire 
plain  single  tie 

Cement 

115 

Average  of  2  pulls.    The  wire  untwisted. 

No.  14  wire  around  post 

Cement 

no 

Average  of  3  pulls.    The  wire  untwisted. 

Cast  staple  holder  with 

ordinary  1%  inch  staple 

driven  into  it 

Cement 

85 

Ave.  of  2  pulls.    Staple  pulled  out  of  holder. 

Cold  shut-link  in 
single  staple 

Cement 

83 

Ivink  opened  in  every  case.    Ave.  of  3  pulls. 

Taper  of  Posts. — To  obtain  the  maximum  strength  with 
the  least  amount  of  material,  the  cement  post  must  be  so  shaped 
as  to  have  its  greatest  strength  at  the  ground  line. 

By  making  the  post  of  uniform  size  from  the  base  to  the 
ground  line,  no  material  is  wasted.  The  post  may  then  be  tapered 
from  the  ground  line  to  the  top.  It  has  been  found  that  in  a  5-inch 
post  which  projects  4  feet  above  the  ground,  a  taper  of  one  inch  on 
each  side  from  the  ground  line  to  the  top,  insures  almost  equal 
strength  throughout.  This  design  gives  more  strength  with  less 
material  than  those  with  the  continuous  taper. 


Cement  and  Concrete  Fence  Posts.  ii 

PART  II. 

THE    EXPERIMENTS 

These  experiments  were  conducted  for  the  purpose  of  deter- 
mining the  method  of  building  the  best  posts  at  the  least  cost. 

Apparatus. — Various  commercial  molds  of  different  shapes 
and  construction  were  secured.  In  each  of  these  molds  sev- 
eral posts  were  made  in  order  to  determine  the  practicability  of 
the  mold ;  also  the  best  combination  of  mixtures  and  reinforcements. 

The  Farm  Mechanics  Department  designed,  built  and  used  a 
simple  home  made  mold  which  makes  a  post  of  uniform  size  from 
the  base  to  the  ground  line  with  a  rapid  taper  from  the  ground 
line  to  the  top.     (See  Fig.  i.) 

A  shed  which  was  closed  on  all  sides  with  a  sliding  door  on  the 
east  was  used  as  the  work  and  curing  room. 

Materials — The  sand  and  gravel  used  was  clean  and 
sharp,  with  all  sizes  of  grains  varying  from  small  to  large.  There 
was  a  very  small  percentage  of  mica  in  the  sand,  which  was  objec- 
tionable. One  brand  of  Portland  cement  was  used  for  making 
all  posts. 

A  total  of  238  line  posts  and  8  comer  posts  were  built  and 
tested  during  the  experiment,  the  records  of  which  are  found  in  the 
following  tables : 

Cost  of  Materials. — In  figuring  cost  of  materials  the  following 
prices  were  used : 

Sand  and  gravel,  $1.00  per  cubic  yard. 
Cement,  60  cents  per  sack. 
New  reinforcement,  4  cents  per  pound. 
Old  barbed  wire,  2  cents  per  pound. 

The  Test. — In  making  the  test,  the  posts  were  placed  under 
as  near  fence  conditions  as  possible.  All  line  posts  were  set  and 
firmly  tamped  into  the  ground  so  that  4  feet  and  one  inch  pro- 
jected above  the  surface.  By  means  of  a  wire,  a  dynamometer  was 
attached  to  the  post  exactly  4  feet  from  the  surface  of  the  ground. 
A  steadily  increasing  force  was  applied  to  the  dynamometer  by 
means  of  a  block  and  tackle,  until  the  first  visible  crack  appeared 
in  the  post  when  a  reading  was  made.  The  force  was  then  in- 
creased until  the  post  gave  away  completely  when  the  final  reading 
was  made. 

In  making  the  posts  enough  of  the  mixture  was  provided  for 
the  construction  of  three  posts  at  once.  The  three  were  cured  alike 
for  60  days  and  were  tested  at  the  same  time.  The  tables  show 
the  average  results  of  the  test  on  the  three  posts  as  one. 

In  the  reinforcement  the  short  wires  mentioned  are  two  feet 
long  and  are  placed  in  the  post  so  the  top  extends  about  12  inches 


12  The  Colorado  Experiment  Station 

above  the  ground  line  and  the  bottom  about  12  inches  below.  One 
of  these  extra  wires  is  placed  in  the  face  side  of  the  post  and  tlie 
other  in  the  back,  so  that  they  help  to  bear  the  strains  on  the  post. 
In  case  of  four  extra  wires,  one  is  placed  in  each  corner  of  the 
post  with  the  other  reinforcement  wires. 

TABLE  NO.  1. — ^Poured  and  Tamped  Posts.* 

Size,  5x5  inches  from  base  to  ground  line,  tapering  to  3x3  inches  at 
top.  Length,  6  feet  6  inches.  Cured  weight,  115  to  120  pounds.  Mixture, 
1  part  cement  and  3  parts  sand  by  measure.  Cost  for  cement  for  posts, 
16.2  cents;  sand,  3.7  cents.    For  cost  of  reinforcement,  see  table. 


COST 

FINAI,   BREAK 

REINFORCEMENT 

Poured  Posts 

Tamped  Posts 

Kind  of  Wire 

Weight 
per 
post 

Cost 
per 
post 

Cost  of 

Material 

in  each 

Post 

Pounds 

to 

break 

Remarks 

Pounds 

to 
break 

Remarks 

No.  10,  4  twisted 
strands  of  2  wires 

2H 

10.0c 

29.9c 

307 

Wires  broke 

240 

Mixture  broke, 

wires  did  not 

break 

No.  10,  8  strands 
crimped 

2!/2 

10.0c 

29.9c 

254 

Wires  slipped 
and  finally 
broke 

263 

Wires  slipped,  did 
not  break 

No.  6,  4  long- wires 
hooked  at  ends 

2% 

10.6c 

30.5c 

232 

All  wires 
slipped 

184 

All  wires  slipped 

New  barbed,  4 
long  strands 

1% 

6.6c 

26.5c 

188 

Wires  broke 

(Post  was  130 

days  old) 

123 

Wires   broke 

Old  barbed,  4 
long  strands 

1% 

3.3c 

23.2c 

158 

Wires  broke 

128 

Wires    broke 

New  barbed,  4 
long  and  2  short 

2 

8.0c 

27.9c 

198 

Wires    broke 

Old  barbed,  4 
long  and  2  short 

2 

4.0c 

23.9c 

200 

Mixture  broke 

above  extra 

wires 

Old  barbed,  4 
long  and  4  short 

2% 

5.5c 

25.4c 

229 

IvOng  wires 
broke  above 
extra  wires 

No.  10,  twisted 
4  long  and  2  short 

3 

12.0c 

31.9c 

290 

Extra  wires 
did  no  good 

160 

Extra  wires  did  no 
good 

*  This  table  is  a  summary  of  Tables  1  and  2,  Bulletin  148,  Colo.  Exp. 


Sta. 


Amount  of  Labor  Required  for  Making  Posts. — No  definite 
statements  can  be  made  as  to  the  amount  of  time  required 
to  make  a  cement  or  concrete  fence  post.  The  amount  of 
time  will  vary  with  conditions,  handiness  of  materials,  methods 
of  mixing,  etc.  According  to  data  obtained  in  the  experiment,  two 
men  mixing  by  hand,  with  everything  reasonably  handy,  can  make 
from  three  to  five  5-inch  poured  line  posts  per  hour.  Figuring  labor 
at  $2.00  per  day,  ten  hours  for  each  man,  the  cost  for  making  a  post 
would  amount  to  about  10  cents  each.  Three  men  with  a  small  home 
made  mixer  and  a  two  horse-power  gasoline  engine  for  driving  it, 


Cement  and  Concrete  Fence  Posts. 


13 


would  be  able  to  make  at  least  twice  as  many  posts  as  two  men 
w^orking  by  hand  and  the  cost  for  making  would  be  very  much  less. 

The  Effect  of  Alkali  on  Cement  and  Concrete  Posts. — It  has 
been  found  that  some  soils  contain  an  excessive  amount 
of  alkali,  which  has  a  tendency  to  destroy  concrete  work. 
While  no  experimental  work  has  been  done  to  test  the  effect 
of  such  soils  upon  cement  or  concrete  posts,  it  has  been  conclusively 
proven  that  cement  drain  and  sewer  tiles  which  come  in  contact 
with  water  w^hich  has  percolated  through  these  alkali  soils  are  soon 
destroyed. 

While  it  might  be  possible  that  the  action  on  cement  or  con- 
crete posts  would  be  slower  than  in  case  of  the  tiles,  it  is  probable 
that  the  post  would  eventually  be  destroyed. 

For  further  information  in  regard  to  the  effect  of  alkali  on 
cement  construction  see  Bulletin  No.  69,  of  the  Montana  Agricul- 
tural Experiment  Station,  and  Bulletin  No.  132,  Agricultural  Ex- 
periment Station  of  the  Colorado  Agricultural  College. 

TABLE  NO.  2. — Poured  and  Tamped  Posts.* 
Size,  5x5  inches  from  base  to  ground  line,  tapering  to  3x3  Inches  at 
top.     Length,  6  feet  6  inches.     Cured  weight,  115  to  120  pounds.    Mixture, 
1  part  cement  andCJ> parts  sand,  by  measure.     Cost  for  cement  per  post, 
iftrt"  cents;  sand, j^^ cents.    For  cost  of  reinforcement,  see  table. 


4^ 

^^ 

COST 

FINAI.  BREAK 

REINFORCEMENT 

Poured  Posts 

Tamped  Posts 

^ind  of  Wire 

Weight 
per 
Pjst 

Cost 
per 
post 

Cost  of 
material  in 
each  post 

Pounds 

to 
break 

Remarks 

Pounds 

to 

break 

Remarks 

No.  10,  4  twisted 
strands  of  2  wires 

I'A 

10.0c 

26.9c 

222 

Mixture  broke, 

wires  not  well 

placed 

192 

Wires 
broke 

No.  6,  4  long  wires 
hooked  at  ends 

2H 

10.6c 

27.5c 

222 

Wires  slipped 

162 

Wires 
slipped 

No.  10,  twisted 
4  long  and  2  short 

3 

12.0c 

28.9c 

322 

Mixtures  and 
wires  about  equal 

Old  barbed  4  long 
strands 

1^3 

3.3c 

20.2c 

95 

Wires  broke, 
poorly  placed 

137 

Wires 
broke 

Old  barbed,  4  long 
and  2  short 

2 

4.0c 

20.9c 

127 

Poor  wire.  Wires 
broke 

142 
170 

Wires 
broke 

New  barbed,  4  long 
and  2  short 

2 

8.0c 

24.9c 

172 

Wires  well  placed, 
cement  broke 

Wires  not 
well  placed 

Old  barbed,  4  long 
and  4  short 

2% 

5.5c 

22.4c 

196 

Wires 
broke 

New  barbed,  4  long 
strands 

iH 

6.6c 

23.5c 

160 

Wires 
broke 

Sta. 


*  This  table  is  a  summary  of  Tables  3  and  4,  Bulletin  148^  Colo.  Exp. 


14 


The  Colorado  Experiment  Station 


TABLE  NO.  3. — Poured  and  Tamped  Posts.* 

Size,  5x5  inches  from  base  to  ground  line,  tapering  to  3x3  inches  at 
top.  Length,  6  feet  6  inches.  Cured  weight,  110  to  112  pounds.  Mixture, 
1  part  cement  and  5  parts  sand,  by  measure.  Cost  for  cement  per  post,  17 
pounds,  10.2  cents;  sand,  1  cubic  foot,  3.7  cents.  For  cost  of  reinforce- 
ment, see  table  below. 


CEME^ 

rT 

COST 

FINAI,  BREAK 

REINFOR 

Poured  Posts 

Tamped  Posts 

Kinds  of  Wire 

Weight 

per 

Post 

Cost 
per 

Post 

Cost  of 
material  in 
each  post 

Pounds 

to 
break 

Remarks 

Pounds 

to 

break 

Remarks 

No.  10,4  twisted 
strands  of  2 
wires 

2M 

10.0c 

23.9c 

235 

Mixture  broke 
(poor) 

97 

Mixture  not 
strong  enough 

No.  10,  twisted 
4  long  and  2 
short 

3 

12.0c 

25.9c 

220 

Extra  wires  did  no 
good 

98 

Posts  split 
Mixture  weak 

Old  barbed,  4 
long  strands 

iH 

3.3c 

17.2c 

113 

Wires  broke 

117 

Wires  broke 

Old  barbed,  4 
long  and  2 
short 

2 

4.0c 

17.9c 

137 

Mixture  and  wires 
about  equal 

113 

Mixture  and 
wires  about 
equal 

New  barbed,  4 
long  strands 

1^3 

6.6c 

20.5c 

123 

Mixture  and  wires 
about  equal 

108 

Mixture  and 
wires  about 
equal 

New  barbed,  4 
long  and  2 
short 

2 

8.0c 

21.9c 

140 

Wires  broke 

103 

Wires  poorly 
placed 

No.  14,  4  twist- 
ed strands  of 
3  wires  each 

12.^ 

6.6c 

20.5c 

130 

Wires  broke 

No.  14,  4  long 
and   2  short,  3 
twisted  strands 
each 

2 

8.0c 

21.9c 

175 

Wires  and  mixture 
about  equal 

Sta. 


This  table  is  a  summary  of  Tables  5  and  7,  Bulletin  148,  Colo.  Exp 


Cement  and  Concrete  Fence  Posts.  15 

TABLE  NO.  4. — Poured  Posts.* 
Size,  4x4  inches  at  base,  tapering  to  3x3  inches  at  top.     Length,  •} 
feet  6  inches.     Cured  weight,  80  pounds. 


COST  OF  MATERIAL  AND  FINAI.  BREAK 

REINFORCEMENT 

Mixture,  1  part  ce- 
ment and  3  parts 
sand. 

Mixture,  1  part  ce- 
ment and  4  pans 
sand. 

Kind  of  Wire 

Weight  per 
post  in  lbs- 

Cost 
per  Post 

Cost 

of  Material 

in  Post 

Pounds  to 
break  post 

Cost 

of  Material 

in  Post 

Pounds  to 
break  post 

No.  10,  4  twisted 
strands  of  2  wires 

zy. 

10.0c 

23.3c 

183 

20.6c 

168 

Old  barbed,  4  long 
strands 

IH 

3.3c 

16.6c 

108 

13.9c 

65 

New  barbed.  4  long 
strands 

1% 

6.6c 

19.9c 

105 

17.2c 

88 

No.  14,  4  strands  of  3 
twisted 

1% 

6.6c 

19.9c 

102 

17.2c 

62 

No.  14,  4  long  and  2 
short  strands  of  3 
twisted 

2 

8.0c 

21.3c 

185 

♦  This  table  is  a  summary  of  Tables  6  and  8,  Bulletin  148,  Colo.  Exp. 


Sta. 


The  Three  Cornered  Post. — The  following  conclusions  are 
drawn  after  testing  23  triangular  posts.  Size,  7  inches  on 
each  side  at  the  bottom,  tapering  to  5  inches  on  each  side  at  the 
top.  Mixture,  i  part  cement  and  3  parts  sand,  by  measure.  Cost 
of  material  varying  from  14  cents  to  19  cents  each. 

The  three  cornered  post  which  is  advocated  to  some  extent, 
does  not  have  as  many  points  in  its  favor  as  it  may  seem.  In  the 
first  place  an  equal  amount  of  reinforcement  in  each  comer  of  the 
post  cannot  make  a  post  of  equal  strength  from  two  opposite  direc- 
tions. If  a  force  is  brought  to  bear  against  one  of  the  flat  sides 
of  the  post  towards  the  opposite  corner,  the  material  in  the  corner 
will  crush  long  before  the  wires  will  break  on  the  side  from  which 
the  force  is  exerted.  On  the  other  hand,  if  a  force  is  brought  to 
bear  against  one  comer  of  the  post  towards  the  opposite  flat  side, 
ihe  single  reinforcement  in  the  corner  will  break  before  the  uiixttire 
has  begun  to  crush  on  the  flat  side. 

An  extra  reinforcement  in  the  comer  on  which  the  force  is 
exerted  towards  the  opposite  flat  side  will  make  it  practically  as 
strong  as  the  flat  side.  But  when  the  force  is  again  applied  to  the 
flat  side  towards  the  single  corner  which  is  doubly  reinforced,  the 
mixture  in  the  corner  gives  away  too  soon  and  it  is  no  better  than 
with  but  a  single  reinforcement. 


i6 


The  Colorado  Experiment  Station. 


TABLE  NO.  5. — Poured  Posts. 

Size,  5x5  inches  from  base  to  ground  line,  tapering  to  3x4  inches  at 
top.  Length,  6  feet  6  inches.  Cured  weight,  115  to  120  pounds.  Mixture, 
1  part  cement,  3  parts  sand,  and  3  parts  gravel,  by  measure.  Cost  of 
cement  per  post,  14  pounds,  8.4  cents;  sand  and  gravel,  1  cubic  foot,  3.7 
cents.    For  cost  of  reinforcement,  see  table  below. 


REINFORCEMENT 

TEST 

COST              REMARKS 

Kind  of  Wire 

Weight 

Per  Post 

I.bs. 

Cost 
Per 
Post 

Final 
Break 
in  Lbs. 

lyocation  of 
Break  Above 

or  Below 
Ground  lyine 

Cost  of 

Materials 

in  Post 

New  Wire  is  Fig- 
ured at  4c  per 
I,b.  and  Old  Wire 
at  2c  per  Lb. 

4  strands  of  2 
wires  twisted 
No.  10-- 

2Vi 

10.0c 

218 

Ground  line 
Ground  line 
4  in.  below 

22.1c 

Wires  broke  on  2 
and  mixture 
broke  on  one 

4  long  and  2 
short  twisted 
strands  No.  10 

3 

12.0c 

330 

4  in.  above 
12  in.  above 
4  in.  below 

24.1c 

Wires  broke 

4  long  strands 
old  barbed 
wire 

l?/3 

3.3c 

110 

Ground  line 
Ground  line 
Ground  line 

15.4c 

wires  broke 

4  long-  and  2 
short  old 
barbed  wire- 

2 

4.0c 

118 

20  in.  above 
24  in.  above 
15  in.  above 

16.1c 

Wires  broke, 
not  well 
placed 

4  long  strands 
new  barbed 

l?S 

6.6c 

143 

4  in.  below 
Ground  line 
Ground  line 

18.7c 

Wires  broke 

4  long  and  2 
short  new 
barbed  wire. 

2 

8.0c 

123 

Ground  line 
3  in.  above 
10  in.  above 

20.1c 

Wires  broke 

4  long  strands 
of  3  twisted 
wires,  No.  14 

l?i 

6.6c 

123 

Ground  line 
27  in.  above 
Ground  line 

18.7c 

Wires  broke 

4  long.  2  short 
strands  of  3 
twisted  No.  14 

2 

8  0c 

143 

Ground  line 
7  in.  below 
4  in.  below 

20.1c 

Mixture  broke  on 
two  and  wires 
broke  on  one. 

Cement  and  Concrete  Fence  Posts. 


17 


TABLE  NO.  6. — Corner  Posts. 

Size,  8x8  inches  from  base  to  ground  line,  tapering  to  5x5  inches  at 
top.  Length,  8  feet.  Cured  weight,  360  pounds.  Mixture,  1  part  cement, 
2  parts  sand,  and  3  parts  of  gravel,  by  measure.  Cured  90  days.  Cost 
for  cement  per  post,  51  pounds,  30.6  cents;  sand  and  gravel,  3  cubic  feet, 
11.1  cents.  For  cost  of  reinforcement,  see  table  below.  Test  shows  pull 
exerted  in  pounds  as  by  each  of  two  fences  pulling  at  right  angles. 


REINFORCEMENT 

TYPE 

TEST 

COST 

REMARKS 

Kind  of  Rein- 
forcement 

Weight 

Per  Post 

I.bs. 

Cost 
Per 
Post 

Poured 

or 
tamped 

First 
Crack 
in  Ivbs. 

Final 
Break 
in  Lbs. 

Location 
of  Break 

Cost  of 
Mater- 
ial per 
Post 

All  reinforcements 
figured  at  4c  pound 

excepting  old 
barbed  wire  at  2c. 

2-8  ft.  and  2-5  ft 
pieces  ^  in.  rod 
on  tension  side 

16 

64c 

poured 

7200 

8500 

at  brace 

11.057 

Short  wires  extend- 
ed from  below 
ground  line  to 
above  brace  line 

Same  as  above 

16 

64c 

tamped 

5050 

5600 

at  brace 

1.057 

Short  wires  extend- 
ed from  below 
ground  line  to 
above  brace  line 

14  strands   old 
barbed  wire  on 
tension  side. 

8 

16c 

tamped 

6300 

7300 

at  brace 

.577 

Mixture  broke 

Same  as  above 

8 

16c 

poured 

5900 

7400 

at  brace 

.577 

Mixture  broke 

10  twisted 
strands  No.  10. 
on  tension  si«le 

8 

32c 

tamped 

5400 

7300 

4  in. 
below 
brace 

.737 

Mixture  broke 

Same  as  above 

8 

32c 

poured 

6300 

6650 

4  in. 
above  brace 

.737 

Mixture  broke 

Size,  7x7  inches  at  base,  tapering  to  5x5  inches  at  top.  Length,  8 
feet.  Cured  weight,  250  pounds.  Mixture,  1  part  cement,  2  parts  sand, 
and  3  parts  gravel,  by  measure.  Cured  90  days.  Cost  of  cement  per  post, 
36  pounds,  21.6  cents;  sand  and  gravel,  2  cubic  feet,  7.4  cents.  For  cost 
of  reinforcement,  see  table  below. 


REIN  FORCEMENT 

TYPE 

TEST 

COST 

REMARKS 

Kind  of  Rein- 
forcement 

Weight 

Per  Post 

Lbs. 

Cost 
Per 
Post 

Poured 

or 
tamped 

First 
Crack 
in  Lbs. 

Final 
Break 
in  Lbs. 

Location 

of 

Break 

Cost  of 
Mater- 
ial Per 
Post 

All  reinforcements 
figured  at  4c  pound 

excepting  old 
barbed  wire  at  2c 

8  strands  old 
barbed  wire  2 
in  each  comer 

43^ 

9c 
2c  lb. 

poured 

2700 

3600 

at  braces 

$0.38 

Mixture  broke 

8  strands  new 
barbed  wire  2 
in  each  comer 

AH 

18c 
4c  lb. 

poured 

3225 

4050 

at  braces 

.47 

Mixture  broke 

HOIvLOW   POSTS. 

It  has  been  suggested  that  the  cement  and  concrete  posts  should 
be  made  hollow.  The  hollow  post  would  require  less  mixture  and 
it  would  also  be  lighter.  As  the  material  in  the  center  of  the  post 
does  not  have  a  good  opportunity  to  act  to  the  best  advantage  in 
cr  mpression,  it  is  argued  that  the  strength  of  the  hollow  post  would 
be  nearly  as  great  as  that  of  the  solid  post. 


i8  The  CoIvOrado  Experiment  Station. 

In  case  time  is  of  little  value  it  would  probably  prove  more 
economical  to  build  hollow  posts.  As  the  amount  of  reinforcement 
is  not  affected  by  the  change  from  the  solid  to  the  hollow  post,  only 
the  saving  in  cement,  sand  and  gravel  need  be  considered.  It  is  an 
easy  matter  to  compute  the  saving  accomplished  by  the  making  of 
hollow  posts,  and  then  by  knowing  the  cost  of  labor,  the  economy 
of  building  them  may  soon  be  calculated.  With  cement  at  55  cents 
per  sack  and  sand  at  $1.00  per  yard,  one  cubic  foot  of  i  to  4  mixture 
costs  18  cents.  If  a  i^  inch  hole  were  to  be  left  in  the  center  of  a 
post  7  feet  long  about  ij^  cents'  worth  of  material  would  be  saved. 
With  labor  at  15  cents  per  hour,  6  minutes  might  be  given  to  the 
extra  work  of  making-  the  post  with  the  hollow  core. 

In  case  of  alkali  soils  the  hollow  center  gives  additional  ex-^ 
posed  surface  upon  which  the  alkali  may  act.     In  a  4-inch  square 
post  with  a  1%  inch  core,  the  extra  surface  amounts  to  about  28 
per  cent,  of  the  original  lateral  surface. 

Finally  there  is  a  serious  question  as  to  the  relative  strength 
and  durability  of  the  hollow  post  as  compared  with  the  solid  one. 

CORNER  POSTS  AND  GATE  POSTS. 

In  the  building  of  a  fence  with  cement  or  concrete  posts,  the 
corner  and  gate  posts  must  be  especially  strong,  so  as  to  prevent  the 
pull  of  the  wires  coming  upon  the  line  posts.  All  the  pull  of  the 
wires  should  be  borne  by  the  corner  or  gate  posts.  With  this  in 
mind  the  designer  should  aim  not  only  to  build  a  very  strong  post, 
but  the  system  of  bracing  should  receive  special  attention. 

As  the  cement  posts  are  not  as  strong  as  wood  posts,  we  can- 
not use  the  same  bracing  systems,  which  are  so  commonly  in  use 
in  wood  post  fence  construction.  It  has  been  found  advisable  to 
place  the  brace  so  that  it  supports  the  post  at  a  point  very  little,  if 
any,  above  the  middle  of  the  post.  For  the  reason  that  the  posts 
are  strong  in  compression,  but  do  not  stand  as  much  pull  as  wood 
posts,  it  proves  advisable  to  place  the  brace  against  the  brace  post 
at  least  one  foot  below  the  ground  line;  thus  the  post  distributes 
the  pressure  at  the  end  of  the  brace  against  an  area  of  ground  equal 
to  the  surface  covered  on  the  opposite  side  of  the  post. 

There  should  be  several  wires  connecting  the  brace  post  and 
the  corner  or  gate  post  together.  These  wires  should  be  placed 
under  the  ground  at  a  depth  of  about  one  foot.  By  having  these 
wires  tight  the  corner  post  cannot  move  unless  the  brace  post  moves, 
and  as  this  is  securely  fastened  to  it,  the  whole  becomes  a  unit, 
offering  a  rigid  resistance  to  the  pull  of  the  fence. 

In  case  of  a  corner  post,  the  wires  may  be  fastened  by  wrap- 
ping them  around  it,  but  the  most  satisfactory  way  is  to  cast  wire 
staples  in  the  post.    These  staples  should  extend  into  the  post  far 


Cement  and  Concrete  Fence  Posts.  19 

enough  to  be  wrapped  around  one  or  more  of  the  reinforcement 
wires. 

The  hinges  for  gates  may  also  be  cast  in  the  posts  when  it  is 
desired  to  do  so. 

Corner  and  gate  posts  are  usually  reinforced  in  the  same  way 
as  line  posts.  It  is  unnecessary,  however,  to  place  reinforcement 
wires  on  the  inner  sides  of  the  corner  posts,  as  the  outer  sides  bear 
almost  all  of  the  tension. 

With  the  tapered  posts,  it  is  desirable  to  construct  the  face 
sides  straight;  this  brings  all  of  the  taper  on  the  other  two  sides. 
Small  lugs  or  shoulders  should  be  cast  on  eacli  brace  side  of  the 
post,  against  which  the  brace  is  placed. 

The  ordinary  five-inch  line  post  proves  to  be  strong  enough  to 
act  as  a  brace  post  for  an  eight-inch  corner  post. 

The  following  table  gives  a  summary  of  breaking  strength  and  cost 
of  materials  of  some  of  the  best  poured   posts,   which  were   made  and 
sted  in  this  experiment. 


REINFORCEMENT 

MIX-    DESCRIP- 
TURE,      TION 

41^ng 

No.  10 

Twisted 

4  long  2 
short  No. 
10  twist- 
ed 

4  long 
New 
Barbed 
Wire 

4  long 

Old 
Barbed 

Wire 

4  long 
2  short 

new 
barbed 

4  long 
2  short 

old 
barbed 

3  long 

No.  1958 

in  .band 

iron 

4  loTig 
4  short 

old 
barbed 

6  long 

old 
barbed 

1  to3 

Ground 
line  5x5 
top  3x3 

307  lbs. 
29.9c 

290  lbs. 
31.9c 

188  lbs. 
26.5c 

158  lbs. 
23.2c 

none 
none 

200  lbs. 
23.9c 

1  to  4 

Ground 
line  5x5 
top  3x3 

222  lbs. 
26.9c 

322  lbs. 

28.9c 

none 
none 

95  lbs. 
20.2c 

172  lbs. 
24.9c 

127  lbs. 
20.9c 

Ground 
^  1     line  5x5 
1  to  5  1       lop  3x3 

235  lbs. 
23.9c 

220  lbs. 
25.9c 

123  lbs. 
20.5c 

113  lbs. 
17.2c 

140  lbs. 
21.9c 

137  lbs. 
17.9c 

lto3 

Base  4x4 
top  3x3 

183  lbs. 
23.3c 

none 
none 

105  lbs. 
19.9c 

108  lbs. 
16.6c 

lto4 

Base  4x4 
top  3x3 

168  lbs. 
20.6c 

none 
none 

88  lbs. 
17.2c 

65  lbs. 
13.9c 

lto33 

Ground 
line  5x5 
top  3x3 

218  lbs. 
22.1c 

230  lbs. 
24.1c 

143  lbs. 
18.7c 

110  lbs. 
15.4c 

123  lbs. 
20.1c 

118  lbs. 
16.1c 

1  to3 

Base  5x5 

top  3x3 

horse  shoe 

shape 

202  lbs. 
23.3c 

133  lbs. 
16.6c 

• 

157  lbs. 
22  3c 

148  lbs. 
18.8c 

;  Triangular 
Base  7x7 
to  3    !    top  5x5 

110  lbs. 
18.0c 

147  lbs. 
15.9c 

20 


L^iNi    OTATION. 


Strength  of  cement  posts  compared  to  new  wood  posts  tested  under 
like  conditions. 


KIND  OF  POST 

( 

SIZE  OF  POST 

BREAKING  STRENGTH 

REMARKS 

(1)     Best  cement  post 
tested 

5x5  in.  at  ground  line 
tapering  to  3x3.in.  at  top 

322  lbs. 

(2)    Cement 

Same  as  above 

307  lbs. 

(3)     Cement 

4x4  in.  at  base  tapering 
to  3x3  in.  at  top 

185  lbs. 

The  post  was  3.6x 
3.6  in.  at  ground 

(4)     Split  cedar  (new) 

3.6x3.6  in.  at  ground 
line 

613  lbs. 

Same  size  at  ground 
as  No.  3  above 

White  pine  '  new) 

4x4  in.  at  ground  line 

2000  lbs. 

Red  spruce  (new) 

4^x4K  in.  at  ground 
line 

2400  lbs. 

Red  spruce  fnew) 

5x5  in.  at  ground  line 

3350  lbs. 

CONCLUSIONS. 

Poured  posts  are  easier  to  make  than  tamped  ones.  They  are  some- 
what more  expensive  because  one  mold  will  make  but  one  poured  post  per 
day,  while  the  same  mold  may  be  used  for  making  as  many  tamped  posts 
as  the  builder  can  mix  and  tamp  in  the  same  time. 

According  to  the  tests  made  poured  posts  are  a  little  over  25  per  cent 
stronger  than  tamped  ones  of  the  same  size,  mixture  and  reinforcement. 

Poured  posts  are  not  so  porous  as  the  tamped  ones  and  are  therefore 
more  nearly  water  proof,  thus  making  them  better  able  to  withstand  tha 
action  of  frost  and  alkali. 

The  poured  post  is  enough  better  in  every  respect  to  justify  its  con- 
struction and  use  in  preference  to  the  tamped  one. 

Most  commercial  molds  make  a  post  which  tapers  from  the  base  to 
the  top,  but  the  most  economical  mold  is  one  which  casts  a  post  as  large 
at  the  ground  line  as  at  the  base,  tapering  from  the  ground  line  to  the 
top.     Fbr  a  description  of  this  form  of  mold,  see  Fig,  4. 

The  best  form  of  post  is  one  which  is  equally  strong  from  all  direc- 
tions. The  square,  or  round  post,  fulfills  this  requirement.  The  tri- 
angular post  does  not  meet  the  requirements  because  it  cannot  be  econ- 
omically constructed  so  as  to  be  equally  strong  from  all  directions. 

To  be  economical,  the  amount  of  reinforcement  should  be  in  propor- 
tion to  the  size  of  the  post  and  strength  of  the  mixture.     See  tables. 

The  material  used  for  reinforcement  should  be  strong,  light  and 
rough  enough  to  permit  the  mixture  to  get  a  firm  grip  upon  it.  It  should 
be  very  rigid,  with  little  or  no  tendency  to  spring  or  stretch. 

The  smooth  reinforcement  tends  to  slip  even  if  hooked  at  the  ends. 

Two  or  more  wires  twisted  together  make  as  satisfactory  a  reinforce- 
ment as  can  be  obtained. 

Crimped  wire  tends  to  straighten  and  thereby  breaks  pieces  out  of 
the  post  at  the  point  of  greatest  stress. 

The  reinforcement  should  be  placed  in  each  corner  of  the  post  at  a 
depth  of  from  %  to  %  of  an  inch  from  the  surface. 

There  are  several  commercial  wire  fasteners  now  found  on  the 
market,  the  most  of  which  are  either  cumbersome  or  expensive.  For  a 
simple  and  satisfactory  fastener,  see  cut  of  fasteners.     (Fig.  5,  A.) 

The  posts  should  be  cured  in  the  shade  for  at  least  60  days,  the  first 
SO  days  of  which  they  should  be  sprinkled  daily. 


Photomount 

Pamphlet 

Binder 

Gaylord  Bros. 

Makers 

Syracuse,  N.  Y. 

PAT.  J«  21,  1908 


^^HH 

^^llP 

^^^f^'[^ /  -[^ 

y  '-  ■'■■■ 

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